<template>
  <div class="upload-file">
    <el-upload :action="uploadFileUrl" :before-upload="handleBeforeUpload" :file-list="fileList" :limit="limit" :on-error="handleUploadError"
      :on-exceed="handleExceed" :on-success="handleUploadSuccess" :show-file-list="true" :data="data" :headers="headers" :drag="drag" ref="upload"
      :auto-upload="autoUpload">
      <!-- 拖拽上传文件 -->
      <i class="el-icon-upload" v-if="drag"></i>
      <div class="el-upload__text" v-if="drag">将文件拖到此处，或<em>点击上传</em></div>
      <!-- 选择文件按钮 -->
      <el-button size="mini" icon="el-icon-upload" v-if="!drag">选取文件</el-button>
      <!-- 上传提示 -->
      <div class="el-upload__tip" slot="tip" v-if="showTip">
        请上传
        <span v-if="fileSize"> 大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b> </span>
        <span v-if="fileType"> 格式为 <b style="color: #f56c6c">{{ fileType.join("/") }}</b> </span>
        的文件
      </div>
    </el-upload>

    <!-- 文件列表 -->
    <transition-group class="upload-file-list el-upload-list el-upload-list--text" name="el-fade-in-linear" tag="ul">
      <li :key="file.uid" class="el-upload-list__item ele-upload-list__item-content" v-for="(file, index) in fileList">
        <el-link :href="`${file.url}`" :underline="false" target="_blank">
          <span class="el-icon-document"> {{ getFileName(file.name) }} </span>
        </el-link>
        <div class="ele-upload-list__item-content-action">
          <el-link @click="handleDelete(index)" type="danger">删除</el-link>
        </div>
      </li>
    </transition-group>
  </div>
</template>

<script>
import { getToken } from '@/utils/auth'

export default {
  name: 'FileUpload',
  props: {
    // 值
    value: [String, Object, Array],
    // 数量限制
    limit: {
      type: Number,
      default: 1
    },
    // 大小限制(MB)
    fileSize: {
      type: Number,
      default: 5
    },
    // 文件类型, 例如['png', 'jpg', 'jpeg']
    fileType: {
      type: Array,
      default: () => ['doc', 'xls', 'ppt', 'txt', 'pdf', 'json']
    },
    // 是否显示提示
    isShowTip: {
      type: Boolean,
      default: true
    },
    // 上传地址
    uploadUrl: {
      type: String,
      default: process.env.VUE_APP_UPLOAD_URL
    },
    // form 列名
    column: [String],
    // 上传携带的参数
    data: {
      type: Object
    },
    // 是否拖拽
    drag: {
      type: Boolean,
      default: false
    },
    // 自动上传
    autoUpload: {
      type: Boolean,
      default: true
    }
  },
  data() {
    return {
      baseUrl: process.env.VUE_APP_BASE_API,
      uploadFileUrl: process.env.VUE_APP_BASE_API + this.uploadUrl, // 上传的图片服务器地址
      headers: {
        Authorization: 'Bearer ' + getToken()
      },
      fileList: []
    }
  },
  watch: {
    value: {
      handler(val) {
        if (val) {
          let temp = 1
          // 首先将值转为数组
          const list = Array.isArray(val) ? val : this.value.split(',')
          // 然后将数组转为对象数组
          this.fileList = list.map((item) => {
            if (typeof item === 'string') {
              item = { name: item, url: item }
            }
            item.uid = item.uid || new Date().getTime() + temp++
            return item
          })
        } else {
          this.fileList = []
          return []
        }
      },
      deep: true,
      immediate: true
    },
    uploadUrl: {
      handler(val) {
        this.uploadFileUrl = process.env.VUE_APP_BASE_API + val
      },
      immediate: true
    }
  },
  computed: {
    // 是否显示提示
    showTip() {
      return this.isShowTip && (this.fileType || this.fileSize)
    }
  },
  methods: {
    // 上传前校检格式和大小
    handleBeforeUpload(file) {
      // 校检文件类型
      if (this.fileType && this.fileType.length > 0) {
        let fileExtension = ''
        if (file.name.lastIndexOf('.') > -1) {
          fileExtension = file.name.slice(file.name.lastIndexOf('.') + 1)
        }
        const isTypeOk = this.fileType.some((type) => {
          if (file.type.indexOf(type) > -1) return true
          if (fileExtension && fileExtension.indexOf(type) > -1) return true
          return false
        })
        if (!isTypeOk) {
          this.msgError(
            `文件格式不正确, 请上传${this.fileType.join('/')}格式文件!`
          )
          return false
        }
      }
      // 校检文件大小
      if (this.fileSize) {
        const isLt = file.size / 1024 / 1024 < this.fileSize
        if (!isLt) {
          this.msgError(`上传文件大小不能超过 ${this.fileSize} MB!`)
          return false
        }
      }
      return true
    },
    // 文件个数超出
    handleExceed() {
      this.msgError(`上传文件数量不能超过 ${this.limit} 个!`)
    },
    // 上传失败
    handleUploadError(err) {
      this.msgError('上传失败, 请重试')
      this.fileList = []
    },
    // 上传成功回调
    handleUploadSuccess(res, file) {
      if (res.code != 200) {
        this.fileList = []
        this.msgError(`上传失败，原因:${res.msg}!`)
        return
      }
      this.msgSuccess('上传成功')
      this.fileList.push({
        name: res.data.fileName,
        url: res.data.url,
        path: res.data.path
      })
      this.$emit(
        'input',
        this.column,
        this.listToString(this.fileList),
        res.data
      )
    },
    // 删除文件
    handleDelete(index) {
      this.fileList.splice(index, 1)
      this.$emit('input', this.column, this.listToString(this.fileList))
    },
    // 获取文件名称
    getFileName(name) {
      if (name.lastIndexOf('/') > -1) {
        return name.slice(name.lastIndexOf('/') + 1).toLowerCase()
      } else {
        return name
      }
    },
    // 对象转成指定字符串分隔
    listToString(list, separator) {
      let strs = ''
      separator = separator || ','
      for (const i in list) {
        strs += list[i].url + separator
      }
      return strs != '' ? strs.substr(0, strs.length - 1) : ''
    },
    // 提交上传
    submitUpload() {
      console.log(this.fileList)
      this.$refs.upload.submit()
    }
  }
}
</script>

<style scoped lang="scss">
.upload-file-list .el-upload-list__item {
  border: 1px solid #e4e7ed;
  line-height: 2;
  margin-bottom: 10px;
  position: relative;
}
.upload-file-list .ele-upload-list__item-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: inherit;
}
.ele-upload-list__item-content-action .el-link {
  margin-right: 10px;
}
::v-deep .el-upload-dragger {
  width: 270px;
  height: 150px;
}
</style>